Horizontal rotating sifter



April 5, 1949- I L. D. GANNON ET AL 2,466,309

HORIZONTAL ROTATING SIFTER Filed July 9, 1946 2 Sheets-Sheet 2 a" I l 67/ 30 v l 20 i r13! 1 39 Larry 17-6 777? Patented Apr. 5, 1949 sr'r g it

T FFICE Larry D. Gannon, Richard E. Gannon, and William V. Gannon, Great Falls, Mont.

Application July 9, 1946, Serial No. 682,216

7 Claims. 1

This invention relates generally to improvements in means for classifying granular materials into their components, and the primary object of the invention is to provide improved apparatus for mechanically separating granular materials according to the relative sizes and shapes of the component particles by means of superimposed circular racks having specially arranged tines, the racks being rotated in the same direction at different speeds so that openings are continually being defined by and between oppositely curving intersecting tines, which openings in effect travel radially outwardly from the common axes of the racks toward the common circumference thereof, whereby the finer particles are permitted to fall through these transitory openings into a subjacent collecting hopper, and larger particles are rejected thereby and caused to travel centrifugally outwardly on the racks, in the course of which travel some of the larger particles fall through the progressively enlarged openings and other larger particles too large to fall through the holes reach and fall from the peripheral edges of the racks into receiving means.

Another important object of the invention is to provide improved separating apparatus of the character indicated above in which the superimposed circular racks can be used in single pairs or in multiple vertical stages of several pairs, with the tines in subjacent pairs similarly spaced or spaced at smaller distances, for acting upon material passed by superjacent racks.

A further important object of this invention is to provide separating apparatus of the character indicated above in which the size, direction of movement, and graduated increase in size of the particle passing openings defined by the superimposed racks may be altered by varying the spacing and curvature of the tines and the relative speed of rotation of the racks.

Other important features and advantages oi the invention will be apparent from the following detailed description and accompanying drawings, wherein a non-limitative embodiment of this invention is set forth merely for illustrative purposes.

In the drawings:

Figure 1 is a transverse vertical section.

Figure 2 is a top plan view.

Figures 3 and 4 are horizontal sections taken on the lines 3-3 and 4-4, respectively, of Figure 1.

Figure 5 is a plan view of the upper rack.

Figure 6 is a plan view of the lower rack.

. Referring to the drawings in detail, the numeral '3 generally designates the inverted conical collooting hopper supported on the floor 8 by vertical legs 9, and having a discharge conduit ill at its lower end to convey the recovery material to a desired destination. Supported on declining radial arms l l secured to the hopper sides is an axially arranged bearing annulus 22 having an extended upper part it.

The lower rotary rack M comprises a hub in the form of a flat disc i5 having an axial tubular part it which depends below the bearing i2 and has a horizontal wonrn wheel ii on its lower end. The disc it rests and turns on the top of the extended upper part it, and the tubular part [6 turns in the bore l8 oi the bearing 12.

The upper rotary rack it comprises a hub in the form of the flat disc 29 of substantially the same diameter as the lower rack disc l5, and. having a tubular part 2! turning in the bore of the tubular part it of the lower rack hub, and depending below the horizontal worm wheel ii, and itself provided with a worm wheel 22. An anti-friction member or spacer 22' may be used, if desired, between the discs l5 and 2t.

Projecting from the edges of the discs i5 and 29 the corresponding tines 23 and 24, respectively, of the racks M and i9. While the tines are shown projecting in a horizontal plane, it is within the present invention to have the tines arran ed in declining or inclining planes where advancing or retarding efiects upon the material being operated upon are desired, and the effect of the force of gravity upon the travel of the material is to be counteracted.

The tines 23 of the lower rack M are spirally curved in a counter-clockwise direction, as shown in Figure 6, and the spacing of adjacent tines gradually increases toward the outer edges or perimeter of the rack I4. The tines 24 of the upper rack I 9 are similarly spaced and curved, but in a clockwise direction, as shown in Figure 5. The tines may be round or square rods or rods of any other cross-section advantageous for operating upon the material to be separated. In special instances also, the spacing of the tines of the upper and lower racks and that of successively lower racks where such are employed may be different and successively smaller, in order to produce successive separation of finer particles. It is to be noted that the curvature adapted for the tines determines the shape of the holes formed by the intersection of the tines of the racks. It is deisrable, although not necessary, that the tines of the upper and lower racks have wiping contact to increase their scalping action.

As shown in Figure 1, the racks are of substantially the same diameter, with their perimeters reaching to a point at and above the upper edge of the hopper 1, so that particles sustained on the racks as far as this point will be caused to fall off the edges of the racks and into the annular trough 2E. The inner wall 21 of said hopper depends from the upper edge 25 of the hopper 7, while the outer trough wall 28 rises above this point to a level with the upper rack tines 24.

At two or more points the trough 26 has discharge chutes 29 through which the material in the trough discharged thereinto by the action of the racks can fall into and be carried away in containers (not shown), or otherwise disposed of.

Supported in the trough 26 is a conveyor chain 30 having spaced upstanding paddles 3! for advancing the material in the trough to the discharge chutes 29. A sprocket wheel '32 engaged with the chain 30 is supported on a shaft 33 traversing the trough and having a driven pulley wheel 34.

,.For driving the racks M and 19 in the same direction of rotation, in this case counter-clockwise, and at difierent rates of speed, with the upper rack usually being driven faster than the lower rack, an upper radial horizontal shaft 35 is provided which passes through a close fitting hole in one side of the hopper l and has a horizontal worm 36 on its inner end in mesh with the worm wheel I! of the lower rack I l. The outer end of shaft 35 has a drive pulley 3'! cperatively connectible to any suitable source of power (not shown), and inwardly of the pulley 37 is a smaller pulley 38 connected by a belt 39 to the conveyor drive shaft pulley 34.

Another horizontal shaft 49 below and arranged like the shaft 35 has a horizontal worm 4! in mesh with the worm wheel 22 of the upper rack l9. oppositely graduated pulleys 42 and 43 on shafts 35 and #0, respectively, are connected by a belt 44, whereby both racks are driven from the shaft 35 at their coordinated different speeds of rotation and the conveyor chain 30 is moved at the desired speed consistent therewith. As indicated in Figures 3 and l, the worm wheels I! and 22 rotate about a vertical axis within casings 45 and 46, respectively, including enclosures 41 and :38, respectively, for the related worms 36 and M, to exclude therefrom, the separated particles falling into and accumulated in the hopper I.

In operation, the material to be separated, such as wheat, falls through the spout 49 axially upon the disc 20 of the upper rack I 9, whose turning action spreads the wheat evenly thereon and thence upon the combined tines 23 and 24 of both racks, these tines forming openings or holes 50 of varying sizes graduated outwardly from relatively small at the edges of the rack discs to substantially larger at the outer edges of the racks. The curvature of the tines and rotation of the racks in the same direction constantly form new openings at the edge of the upper rack disc 20, which travel outwardly to the outer edges of the combined racks.

The desired particles of wheat or other material fall through the holes 50 into the hopper l to be recovered therefrom, but the overs are scalpecl off by the rotating racks into the trough 26 for disposal through the chutes 29. This scalping is produced by the action of centrifugal force derived from the rotary motion of the racks and the conveying action caused by the differential in speed of the upper and lower racks, the upper rack normally being the faster, Particles lying across any of the holes 58 are kept in a constant state of gentle agitation as they move outwardly on the racks, until the holes 50 thereunder become large enough to pass the particles or they are carried over the edges of the racks into the trough 26.

It will be noted that the above-described separating action is much smoother and more efiicient than the abrupt reciprocating action of present sieve machines with their attendant sieve cleaners, and that the present invention does not involve their frequent jamming and loss of efiiciency.

We claim:

1. A separator for material, comprising two horizontal rotary racks, one rack being superimposed upon the other, each rack including an imperforate center portion and a plurality of spirally curved tines radiating from said center portion, the tines of the two racks being curved in opposite directions, means supporting said racks for coaxial rotation with their tines in closely vertically spaced relation, and means for simultaneously and constantly rotating said disks at diiierent rates of speed, whereby relatively small apertures are initially formed by and between intersecting tines of the two racks at the edges of said imperforate center portions and grow in size and move outwardly toward the outer edges of the racks, so that the finer particles can fall through said relatively small holes with the larger particles being retained.

2. A separator for material, comprising two horizontal rotary racks, one rack being superimposed upon the other, each rack including an imperforate center portion and a plurality of spirally curved tines'radiating from said center portion, the tines of the two racks being curved in opposite directions, means supporting said racks for coaxial rotation with their tines in closely vertically spaced relation, and means for simultaneously and constantly rotating said disks at different rates of speed, whereby relatively small apertures are initially formed by and between intersecting tines of the two racks at the edges of said imperforate center portions and grow in size and move outwardly toward the outer edges of the racks, so that the finer particles can fall through said relatively small holes with the larger particles being retained, an annular trough surrounding said racks to receive the coarser particles falling from the outer edges of the racks, discharge means on said trough, and a conveyor in the trough for moving the material therein to said discharge means.

3. A separator for material, comprising two horizontal rotary racks, one rack being superimposed on the other, each rack including an imperiorate center portion and a plurality of spirally curved tines radiating from said center portion, the tines of the two racks being curved in opposite directions, means supporting said racks for coaxial rotation with their tines in closely verti cally spaced relation, and means for simultaneously and constantly rotating said disks at different rates of speed, whereby relatively small apertures are initially formed by and between intersecting tines of the two racks at the edges of said imperforate center portions and grow in size and move outwardly toward the outer edges of the racks, s'o that the finer particles can fall through said relatively smallholes with the larger particles being retained, a trough surrounding said racks to receive the coarser particles falling from the outer edges of the racks, discharge means on said trough, a conveyor in the trough for moving the material therein to said discharge means, and coordinating operating means connected to said drive means for operating said conveyor at a rate commensurate with the rates of rotation of the racks.

4. A separator for material, comprising two horizontal rotary racks, one rack being superimposed upon the other, each rack including an imperforate center portion and a plurality of spirally curved tines radiating from said center portion, the tines of the two racks being curved in opposite directions, means supporting said racks for coaxial rotation with their tines in closely vertically spaced relation, and means for simultaneously and constantly rotating said disks at dlfierent rates of speeds, whereby relatively small aper tures are initially formed by and between intersecting tines of the two racks at the edges of said imperforate center portions and grow in size and move outwardly toward the outer edges of the racks, so that the finer particles can fall through said relatively small holes with the larger particles being retained, the surface constituted by the overlying and intersecting tines acting to centrifugally move said retained particles outwardly on the racks to fall from the outer edges thereof, said rotating means comprising means for varying the relative speed of said racks so as to change the direction of movement of the particle-passing holes.

5. A device for separating finely divided solid material according to size, comprising a hopper for receiving the particles to be recovered, an annular bearing supported in said hopper, a lower rotary rack having a center disc including a depending tubular part turning in said annular bearing, an upper rotary rack having an imperforate center disc turnably supported on the lower rack disc and having a depending cylindrical part turning in the bore of said tubular part and reaching therebelow, tines projecting outwardly from the edges of both said center discs, the tines of the upper rack curving in the opposite direction from the tines of the lower rack, whereby upon simultaneous rotation of said racks in the same direction at difierent rates of rotation the intersecting and overlying tines define particle-passing openings moving outwardly toward the edges of the racks and gradually increasing in size from the edges of said discs to the outer edges of the racks, and drive means operatively connected to said depending tubular part of the lower rack and to said depending cylindrical part of the upper rack for driving said rack simultaneously in the same direction at constant diiierent rates of speed.

6. A separator for comminuted material containing particles of different sizes, said separator comprising a pair of coaxial rotary racks arranged in closely superimposed relation, said racks being of substantially the same diameter and of similar construction comprising an imperforate center disk and spirally curved tines radiating from the perimeter of the disk, the tines on the individual racks being the same in number and curved in opposite directions, and means for rotating said racks in the same direction at the same time but at different speeds, whereby the tines of the two racks intersect and form spaces between intersecting tines through which particles of material can fall below said racks, said spaces being of minimum size near the disks and increasing in size toward the periphery of the racks whereby material particles of minimum size can fall below the racks near the centers thereof while larger particles are moved outwardly toward the periphery of the racks.

7. A separator for comminuted material containing particles of difierent sizes, said separator comprising a pair of coaxial rotary racks arranged in closely superimposed relation, said racks being of substantially the same diameter and of similar construction comprising an imperforate center disk and spirally curved tines radiating from the perimeter of the disk, the tines on the individual racks being the same in number and curved in opposite directions, and means for rotating said racks in the same direction at the same time but at difierent speeds, whereby the tines of the two racks intersect and form spaces between intersecting tines through which particles of material can fall below said racks, said spaces being of minimum size near the disks and increasing in size toward the periphery of the racks whereby material particles of minimum size can fall below the racks near the centers thereof while particles are moved outwardly toward the periphery of the racks, said tines on each rack being uniformly circumferentially spaced around the disks and being divergently spaced with respect to each other whereby the radially outward ends of adjacent tines are more greatly spaced from each other than the radially inward ends thereof.

LARRY D. GANNON. RICHARD E. GANNON. WILLIAM V. GANNON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 238,844 Russell Jan. 18, 1881 493,521 Rishworth et a1. Mar. 14, 1893 1,078,819 Bartholomai Nov. 18, 1913 FOREIGN PATENTS Number Country Date 12,990 Austria Apr. 1, 1903 442,099 Germany Mar. 23, 1927 426,533 Great Britain Apr. 4, 1935 

